S2: Ch1 Cv 1-8

Front 1

215. Chronic Afib tx?

Back 1

a. Rate control w/β-blocker or calcium channel blocler.
b. Anticoag: Pts w/ “lone Afib (I.e., Afib in the absence of underlying heart disease or other cardiovascular risk factors) under age 60 do not require anticoagulation bc they are at low risk for embolization (aspirin may be appropriate)
c. Tx all other pts w/chronic anticoag (warfarin).

Front 2

216. Cardioversion

Back 2

a. Delivery of a shock that is in synchrony w/the QRS complex: Purpose is to terminate certain dysrhythmias such as PSVT or VT.
b. An electric shock during T wave can cause Vfib, so the shock is timed not to hit the T wave.

Front 3

217. 4 Indications for Cardioversion?

Back 3

1. Afib
2. Atrial flutter
3. VT w/pulse
4. SVT

Front 4

218. Defibrillation?

Back 4

a. Delivery of a shock that is not in synchrony w/the QRS complex: Purpose is to convert a dysrhythmia to normal sinus rhythm.
b. Indications: Vfib, Pulseless VT.

Front 5

219. Automatic Implantable defibrillator?

Back 5

a. When it detects a lethal dysrhythmia, it delivers an electric shock to defibrillate. It delivers a set number of shocks until the dysrhythmia is terminated.

Front 6

220. Indications for Implantable defibrillator?

Back 6

a. Vfib and/or VT that is not controlled by medical therapy.

Front 7

221. Tx of Afib and atrial flutter are similar: what are the 3 main goals?

Back 7

1. Control ventricular rate
2. Restore normal sinus rhythm
3. Assess need for anticoagulation

Front 8

222. What did the Affirm trial show regarding Afib?

Back 8

a. That rate control is superior to rhythm control in tx of Afib.

Front 9

223. What is the risk for CVA in pts w/Afib?

Back 9

a. Pts w/ “lone Afib” : 1% per year
b. Pts w/heart disease: 4 % per year.

Front 10

224. Pathophys of Atrial flutter?

Back 10

a. One irritable automaticity focus in the atria fires at about 250-350 bpm giving rise to regular atrial contractions.
b. Atrial rate between 250-350. Ventricular rate is ½ to 1/3 of the atrial rate.
c. The long refractory period in the AV node allows only one out of every 2 or 3 flutter waves to conduct to the ventricles.

Front 11

225. Causes of Atrial flutter?

Back 11

a. COPD-most common association.
b. Heart disease: rheumatic heart disease, CAD, CHF.
c. Atrial Septal defect.

Front 12

226. Dx of Atrial flutter?

Back 12

a. ECG provides a saw-tooth baseline, w/a QRS complex appearing after every 2nd or 3rd “tooth” (P wave).
b. Saw-tooth flutter waves are best seen in the inferior leads (II, III, aVF).

Front 13

227. Tx of atrial flutter?

Back 13

a. Similar to tx of AFib.

Front 14

228. MAT- Multifocal Atrial Tachycardia?

Back 14

a. Usually occurs in pts w/severe pulmonary disease (e.g., COPD)
b. ECG findings: variable P-wave morphology and variable PR and RR intervals.
c. At least 3 different P-wave morphologies are required to make an accurate diagnosis!
d. Can also be diagnosed by use of vagal maneuvers or adenosine to show AV block w/out disrupting the atrial tachycardia.

Front 15

229. Tx of MAT?

Back 15

a. Involves improving oxygenation and ventilation.
b. If left ventricular function is preserved, acceptable treatments include:
1. Calcium Channel Blockers
2. β-blockers
3. Digoxin
4. Amiodarone
5. IV flecainide
6. IV propafenone.

Front 16

230. What should you use in MAT if LV function is not preserved?

Back 16

a. Digoxin or
b. Diltiazem or
c. Amiodarone

Front 17

231. Can electrical cardioversion be used for MAT?

Back 17

a. No, it is ineffective and should not be used.

Front 18

232. Pathophys of PSVT- Paroxysmal Supraventricular Tachycardia?

Back 18

a. Most often due to reentry

Front 19

233. 2 types of pathophys for PSVT?

Back 19

233. 2 types of pathophys for PSVT?

Front 20

234. AV nodal reentrant tachycardia- 1 cause of PSVT

Back 20

i. Two pathways (one fast and other slow) w/in the AV node, so the reentrant circuit is w/in the AV node.
ii. Most common cause of supraventricular tachyarrhythmia (SVT)
iii. Initiated or terminated by PACs.

Front 21

235. Orthodromic AV reentrant tachycardia- 1 cause of PSVT?

Back 21

a. An accessory pathway between the atria and ventricles that conducts retrogradely.
b. Called a “concealed bypass tract”, and is a common cause of SVTs.
c. Initiated or terminated by PACs or PVCs.

Front 22

236. AV nodal reentrant tachycardia- ECG for PSVT?

Back 22

a. Narrow QRS complexes w/no discernable P waves (P waves are buried w/in the QRS complex).
b. This is bc the circuit is short and conduction is rapid, so impulses exit to activate atria and ventricles simultaneously.

Front 23

237. ECG for orthodromic AV reentrant tachycardia?

Back 23

a. Narrow QRS complexes w/P waves which may or may not be discernible, depending on the rate.
b. This is because the accessory pathway is some distance from the AV node (reentrant circuit is longer), and there is a difference in the timing of activation of atria and ventricles.

Front 24

238. Causes of PSVT?

Back 24

1. Ischaemic heart disease
2. Digoxin toxicity- Paroxysmal atrial tachycardia w/2:1 block is the most common arrhythmias associated w/digoxin toxicity.
3. AV node reentry
4. Atrial flutter w/rapid ventricular response
5. AV reciprocating tachycardia (accessory consumption)
6. Excessive caffeine or alcohol consumption.

Front 25

239. Tx for PSVT?

Back 25

a. Maneuvers that stimulate the vagus delay AV conduction and thus block the reentry mechanism: the Valsalva maneuver, carotid sinus massage, breath holding , and head immersion in cold water (or placing an ice bag to the face)

Front 26

240. Acute tx of PSVT-pharmacologic therapy?

Back 26

a. IV adenosine- agent of choice due to short duration of action and effectiveness in terminating SVTs.
b. IV verapamil, IV esmolol, (β-blocker) or digoxin are alternatives in pts w/preserved left ventricular function.

Front 27

241. DC cardioversion for PSVT?

Back 27

a. If drugs are not effective or if unstable; almost always successful.

Front 28

242. How does Adenosine work for PSVT?

Back 28

242. How does Adenosine work for PSVT?

Front 29

243. How does Verapamil work for PSVT?

Back 29

a. Calcium channel blocker.

Front 30

244. Prevention of PSVT-pharmacotherapy?

Back 30

a. Digoxin is usually the DOC.
b. Verapamil or β-blockers are alternatives.
c. Radiofrequency catheter ablation of either the AV node or the accessory tract (depending on which is the accessory pathway) is preferred if episodes are recurrent and symptomatic.